Light emitting devices used for illumination devices, display devices, traffic lights, sensor devices, and so on are increasingly required to achieve higher output.
A current spreading layer having high impurity concentration can be provided between the light emitting layer and the first electrode. Then, carriers injected from the first electrode are easily spread in the plane of the current spreading layer and the light emitting layer to emit light with high optical output.
Furthermore, fine concave-convex structures can be formed at the surface of the current spreading layer on the light emitting side. This can improve the light extraction efficiency and increase the optical output. The dry etching method can be used to form the fine uneven surface with the concave-convex structures. By using the dry etching method, a fine uneven surface having a size equal to or less than the wavelength of the emission light can be reliably formed with high productivity.
However, use of the dry etching method may result in crystalline defects or damage in the processed region. This may decrease the optical output by long-term operation.